A valve prosthesis is adapted to operate in conjunction with native heart valve leaflets. The prosthesis includes an annulus and a skirt extending from the annulus. The skirt may be configured to be positioned through a native heart valve annulus, and the skirt may be movable between an open configuration permitting blood flow through the skirt and a closed configuration blocking blood flow through the skirt in cooperation with opening and closing of the native heart valve leaflets.
